In EDs throughout the United States, emergency physicians commonly estimate blood loss as part of ongoing evaluation of patients or during procedures. In many scenarios, there may not be other useful indicators of significant blood loss. For example, hematocrit levels are often a poor indicator of acute blood loss. Furthermore, vital signs can remain normal despite large losses, and patients’ own estimates are often not trusted. Accurate blood loss estimates are obviously important if this information is used during the clinical decision-making process. They also help physicians create a complete picture of the severity of the problems patients are experiencing. Unfortunately, previous studies have demonstrated that trauma surgeons, nurses, paramedics, obstetricians, and general surgeons often have difficulties with estimating blood loss accurately. Examining New Data In the Western Journal of Emergency Medicine, a study examined the accuracy of ED physicians in estimating blood loss on different surfaces. In it, 56 ED physicians—consisting of 30 attending physicians and 26 residents—were asked to estimate the amount of moulage blood that was present in four scenarios: 1) 500 mL spilled onto an ED cot. 2) 25 mL spilled onto a 10-pack of 4×4-inch gauze. 3) 100 mL on a T-shirt. 4) 150 mL in a commode filled with water. In the study, only 8% of blood loss estimates fell within 20% of the true value. On average, estimates were more than 100% off from the actual amounts. Estimates were most accurate for the cot scenario and least accurate for the commode scenario. Residents and attending physicians performed about the same in the scenarios assessed. Overall, the analysis adds evidence that ED physicians—like...